The present embodiments relate to particle therapy.
Particle therapy may be used for radiation therapy. Particle therapy includes irradiating a tissue to be treated with high-energy particle radiation. Protons or carbon ions are generally used for irradiation, but other types of particles, such as pions or helium ions, may be used.
Particles interact with the tissue differently than gamma rays. As long as the particles have high energy (e.g., on the order of magnitude of >50 MeV/u), the particle interaction with the tissue is relatively low with respect to gamma rays. The interaction does not increase until after the particles have lost energy when passing through tissue. The interaction with the tissue takes place predominantly along a distance that is on the order of magnitude of a few millimeters and decreases to zero. The particle profile generated in the process is called the Bragg peak. The particle interaction makes it possible to aim the energy of the particle beam in a targeted way at a tumor, for instance, in the interior of the body while sparing the surrounding tissue and organs. The penetration depth of the particles and the site of the maximum effect are determined by the energy of the particle beam. During irradiation, energy levels for protons are generally in the range from 48 MeV/u to 250 MeV/u, and with carbon ions in the range from 85 MeV/u to 430 MeV/u.
A cyclotron is used to accelerate particles to high energy. Electrically charged particles are generated by an ion source and accelerated in the cyclotron, with strong electromagnetic fields in a spiral path, to a target energy level. The particles are expelled from the cyclotron using the fastest spiral path at the periphery of the cyclotron. After the particle beam leaves the cyclotron, the energy level is adjusted, so that the energy of the particle beam is adapted to the desired penetration depth. A selection system is connected downstream of the cyclotron. The selection system may be used to adjust the energy level. A beam transporting system is used to carry the particle beam to the desired treatment place. Further adjustment of the energy level of the particle beam—may occur downstream of the energy selection system.
Cyclotron-based particle therapy systems may accelerate two different types of particles and use the two different types of particles for irradiation. For instance, each type of particle is accelerated in its own cyclotron adapted to that type of particle.